Drilling and lining of drain holes



July 2, 1957 J. s. MocuNr; ETAL DRILLING AND DINING OF DRAIN HOLES 2She'ets-Sheet 1 Filed sept. v13, 1954 97 a www). ,n

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a MCH@ f# JWM .July 2, 1957 J. s. MccuNE ErAL 2,797,893

DRILLING AND LINING oF'bRAIN HoLEs Filed sept. 1s, 1954 A2 sheets-sheet2 T ro/QNEY;

1 u 54a. 2 A n., Em n @a 9 a a w u.. M2994 .m Wx b Q I a z y 1 @u IM.IIIrWII vll. l N M a HHHWUHWHHUMIN.|1r\ m m a J L. VH M United StatesPatentffOiitice 2,797,893 Patented July 2, 1957 DRnLING AND LINING onDRAIN Horns John S. McCune and William E. Hanks, Long Beach, Calif.,assignors to Oilwell Drain Hole Drilling Co., Long Beach, Calif., acorporation of California Application September 13, 1954, Serial No.455,473

Claims. (Cl. Z55- 1.6)

This invention relates to improved apparatus and methods for drillingand lining oil well drain holes, that is, auxiliary holes or boresextending laterally into the producing formation from a main bore.

After a drain hole has been drilled from a main well bore, it isfrequently desirable to advance a liner into the drain hole, forsupporting the walls of the hole against collapse. The present inventionis in certain respects particularly concerned with improvements in themanner of constructing and handling these liners. Especiallycontemplated is a new way of assuring a very direct and positiveconnection of the inner end of the drain hole liner to the main liner inthe main bore of the well. Whereas in many prior arrangements the drainhole liner has not been directly attached to the main liner at all, withthe result that the earth formation was not properly retained againstcollapse into the well at the juncture between the two liners, thepresent invention is particularly concerned with a unique manner offorming between these two liners a very direct and yet easily madeconnection, which acts to effectively retain the formation against suchcollapse at that location.

In accordance with the invention, the main liner is prefferablypreformed, before being lowered into the well, to have one or more wallapertures positioned at the desired drain holes locations. The liner isthen lowered into the well, and drain holes are drilled at the locationsof these preformed liner apertures. After drilling a particular drainhole, a specially formed exible liner is advanced thereinto. This linerpreferably has an upper portion which is a tight or forced fit withinthe aperture of the main liner, so that the desired positive jointbetween the two liners is formed by merely forcing the drain hole linerthrough the aperture.

As the drain hole liner is advanced through the aperture, the liner maybe retained against rotation from a predetermined proper position bymeans of interengaging guide means on the liner and an engagingwhipstock which is utilized for directing the liner. These guide meansmay include a lug positioned in an upper tubular portion of thewhipstock unit, and a guide recess formed on the drain hole liner andadapted to slidably receive the lug. v Such positioning of the drainhole liner is desirable in order that an upper angularly cutoff portionof the drain hole liner may properly connect into the main liner.

An additional feature of the invention residesV in a unique manner ofsupporting the whipstock in the main liner during the drilling and otheroperations. For this purpose, there may be specially designed means onthe main liner and whipstock, which are interengageable to support thewhipstock at a proper location for deecting the drill bit or drain holeliner laterally through the aperture in the main liner. These supportingmeans may include a lug or block attached to the main liner, andreceivable in a mating recess in the whipstock. This block may beattached to the main liner by a shear pin, so that it may be sheared olfof the inner wall of the liner after completion of one drain hole, topermit drilling of another drain hole, or to entirely open the bore inpreparation for other operations.

The above and other features and objects of the present invention willbe better understood from the following detailed description of thetypical embodiment illustrated in the accompanying drawings, in which:

Fig. 1 is a view showing in a well a main liner having preformedapertures or windows into which are connectable a number of liners forlaterally extending drain holes; Fig. 2 is an enlarged View partly insection of a portion of the Fig. 1 main liner;

Fig. 3 is a vertical section through the liner, with a whipstock anddrill string positioned therein;

Fig. 4 is an enlargedrhorizontal section taken on line 4--4 of Fig. 3;

Fig. 5 is a fragmentary view of the lower portion of the whipstock, andshowing the recess by which the Whipstock is supported in the liner;

Fig. 6 is a view showing one of the drain hole liners as it is beinglowered into position in a well;

Fig. 7 is a view corresponding to Fig. 6, but showing the` drain holeliner after being advanced to its ultimate position in the well;

Fig. 8 is a horizontal section taken on line 8 8 of Fig. 6; and

Fig. 9 is a view taken during the drilling of the final drain hole.

' Referring first to Fig. l, we have shown at 10 the main bore of awell, into which is lowered a main liner 11 having the usualperforations 12 through which oil oWs into the liner for deliveryupwardly to the surface of the earth. Liner 11 is connected in anysuitable manner to the lower end of the usual well casing 13. Liner 11is conventional in construction, except that its side wall contains anumber of preformed drain hole openings or windows 14, for placing thernain liner in communication with a number of drain holes to be drilledalong laterally extending courses designated at 15. Before loweringliner 11 into the well, it is determined exactly where the drain holesare to be drilled, and openings 14 are then formed in the liner at thedesired locations. With these openings thus preformed, liner 11 islowered to the Fig. 1 position, and the drain holes are then drilled.

The drain holes are formed by a flexible drilling string 16, which isdirected laterally through liner lopenings 14 by a conventionalwhipstock 17. After a particular drain hole has been drilled, a exibleliner 18 is advanced into the hole to the position of Fig. 9, followingwhich the lnext successive hole is drilled and lined.

Whipstock 17 may be of essentially conventional construction, having anupper tubular or sheath portion 19 -through which drill string 16 orliner 18 are advancable downwardly, and having an inclined detlectingface 20 for deflecting the drill string or drain hole liner laterallythrough one of the main liner openings 14 and into the surroundingformation. Adjacent detlecting face 20, whipstock 17 has the usual sidewindow 21, through which a deected string or liner may advance laterallyout of the whipstock. The whipstock may be removably supported in thewell by a ntunber of support lugs or blocks 22 attached to the innerside of the main liner 11 by studs 23 at locations directly beneath thevarious open- 14. For coaction with blocks 22, whipstock 17 rnlaycontain a vertically extending recess 24 of a width equal to the widthof blocks 22, so that the whipstock may i be supported Ion any of theblocks in the position of Fig.

3, The upper ends of the lugs 22 and recess 24 may be inclined upwardlyand toward the center of the whipstock and main liner, to provide a pairof engageable inclined shoulders for eifecting the desired support ofthe whipstock, and at the same `time preventing the whipstock from`slipping off ofthe lug (by virtue of the inclination of the shoulders).The lever end of recess 24 may open and are downwardly at 26, as seen inFig. 5, so that the whipstock may be easily advanced `downwardly to aposition of support by one of the lugs 22. For a reason that will appearlater, studs 23 are specially formed to be sherared or broken bydownward force exerted against the corresponding block 22.

The drill string 16 for drilling drain holes 15 is longitudinallyexible, and may typically be of the type described more specifically inapplication Ser. No. 279,557, filed March 31, 1952 on Flexible wellDrill Collar, now U. S. Patent 2,712,436, issued July 5, 1955. Thisstring may be formed from a pipe, whose wall is cut at longitudinallyspaced locations along waving lines 27, to divide the pipe into a numberof articuately interconnected segments which are free for limitedrelative movement, thus giving the string as a unit the desiredlongitudinal flexibility. The waving cuts 27 preferably form on thesuccessive string segments a number of interengaging lobes and recesses,which effectively retain thesegments against longitudinal separation,while at the same time permitting their limited relative movement. Thecuts 27 may be formed by la welding torch, the width of the cut beingsucien-tly great to allow looseness between successive segments.

Drill string 16 carries at its lower end the usual drilling bit 28,which acts to drill a drain holeupon rotation l-of the string.Preferably, the whipstock 17 is adapted to be lowered into and removedfrom the well by mea-ns of drill string 16. While this support may beeffected in any of different ways, I have typically land for simplicityillustrated the whipstock supporting connection as comprising anenlargement 29 formed on string 16 and adapted for engagement with ashoulder 30 extending inwardly from the upper tubular portion 19 of thewhipstock. As will be understood, during lowering of string 16 and thewhipstock into a well, enlargement 29 on the drill string is inengagement with the underside of whipstock shoulder 30, so that thestring land whipstock are lowered as a unit. The string is then adaptedto be advanced downwardly for drilling drain hole 15, and during suchadvancement, enlargement 29 yof course advances downwardly away from itsposition of engagement with shoulder 30.

After a drain hole has been drilled the whipstock and drill string areremoved from -the well, following which the drain hole liner 18 ispositioned in the upper tubular portion 19 of the whipstock, and thewhipstock and liner 18 are then lowered downwardly into the well as aunit. The liner 18 is tubular and longitudinally exible, and maytypically be formed essentially the same as flexible ydrill string 16.That is, liner 18 may include a number of interconnected rigid segments31 movably joined together by lobe and recess type connections at 32.The various segments 31 may` contain wall apertures 33, through whichfluid from the earth may flow into the drain hole liner 18 for deliveryto main liner 11. The lower end of drain hole liner 1S mlay carry arounded nose member 36, which may contain fluid passing apertures 37.

The upper end of liexible liner 1S carries a rigid tubular connectormember 34, which is adapted to be tightly connected into one of theopenings 14 in the main liner 11. This upper member 34 has a circularexternal surface 35, which enlarges slightly in diameter in an upwarddirection, land which is adapted to peripherally engage and fit tightlyand closely within opening 14. When ultimately connected int-o the mainliner 11, connector member 34 of the drain hole liner extends downwardlyand outwardly from the main liner rat an angle a such as that seen .inFig. 9. Each of the openings 14 in the main liner may be described asbeing defined by the intersection of the wall of the mlain liner and acylinder extending at the angle a to the main liner. This cylinder has adiameter which is very slightly smaller than the effective diameter ofthe portion of member 34 which is ultimately received in opening 14 inthe- Fig. 7 position (the difference between these diameters beingtypically about 14) so that member 34 is a forced fit in opening 14, andwhen forced downwardly to the Fig. 7 position is very tightly retainedwithin the opening. The upper end of member 34 is cut off in anangularly extending cylindrical plane, of a diameter corresponding tothe internal diameter of main liner 11, and disposed at such an angle tothe upper end 38 of member 34 as to be substantially flush with theinner surface of the main liner in the ultimate Fig. 7 position.

Drain hole liner 18 is lowered into the well at the lower end of a toolstring 39, which may be at least partially flexible, and which carriesat its lower end a member 40 adapted to be removably threadedlyconnected at 41 into the upper end of connector member 34 of liner 18.Member 40 is attached to the tool string 39' by a conventional universaljoint 42, which is adapted to allow universal movement of member 40relative to the tool string, while at theA same time transmitting rotarymotion between these parts. During lowering of liner 18 and whipstock 17into the well, the former is contained within the upper tubular portion19 of the latter, and the whipstock is suitably suspended from thestring, as by engagement'of'an enlargement or shoulder 29a on the toolstring with whipstock shoulder 30. After the whipstock has been againpositioned on one of the support blocks 22, liner 18 may be advanceddownwardly into the previously drilled drain hole 15. Before lowering ofthe liner 18 and whipstock in' the well a positioning block 43 isattached to the inner side of the upper tubular portion of the whipstockby a stud 44. This block is adapted to be received within a verticallyextending slot 45 formed in the side of member 34, to preventadvancement of member 34 downwardly to the Fig. 7 position unless keyingblock 43 and slot 45 are in registering relation. This block and recessthus assure proper positioning of member 34 in opening 14.

To now describe briefly a complete drain hole drilling and liningoperation, as performed in accordance with the present invention, thefirst step after drilling of the main bore and positioning casing 13therein is to preform the apertured production liner 11, with thevarious apertures 14 being formed in the liner prior to lowering. Theseapertures 14 are formed in the liner at predetermined positions, whichare selected from a study of the characteristics of the producingformation. If the formation haspa sufficiently great vertical extent,liner 11 may ybe formed of a number of threadedly interconnected tubularsections or stands.

The liner 11 containing preformed apertures 14 is then lowered into itsillustrated Fig. l position within the main bore 10. As thus lowered,liner 11 contains one of the whipstock positioning block 22 at alocation beneath the central portion of each of the various apertures14. Following positioning of main liner -11 in the well, whipstock 17and drill string 16 are klowered together as a unitV into the well, withthe lower portion of the drill string and bit entirely contained withinthe upper tubular'portion 19 of the whipstock. In this position of thedrill string, the whipstock is supported from the drill string byengagement of string shoulder 29 with the underside of whipstockshoulder 30. The string and whipstock are thus lowered through casing 13and into liner 11, to the Fig. 3 position in which the uppermost supportblock 22, associated with the uppermost aperture 14, is received withinslot 24 in the whipstock, to thus support the whipstock in the Fig. 3position independently of any suspension of the whipstock -by thestring. The string may then be simultaneously rotated and advanceddownwardly, while circulating fluid is supplied to the bit 28 throughthe tubular string, with the result that the bit is deflected laterallyby whipstock face 20, and acts to drill arst and upper one of thelaterally extending drain h oles 15.

fter the rst drain hole has been drilled, string 16 is retractedupwardly into its initial position within the tubular upper portion 19of the whipstock, so that shoulders 29 and 30 again move intoengagement, and the string and whipstock are then elevated as a unitupwardly out of the main bore. While at the surface of the earth, thedrill string is withdrawn entirely from within the whipstock, as may bepermitted by detachment of the shoulder 30 from the whipstock by virtueof a threaded connection at 130. Locating block 43 is then connectedinto the whipstock, liner 18 is positioned within the upper tubularportion of the whipstock and connected to tool string 39, and the uppershoulder 30 is reattached to the Whipstock. In this condition, thewhipstock is supported by engagement shoulder 29a on the tool stringwith the underside of whipstock shoulder 30 of the whipstock, so thatthe liner and whipstock may be lowered together into the hole to theFig. 6 position in which the whipstock is again supported on block 22.

With the whipstock thus supported, string 39 and liner 18 are advanceddownwardly within the whipstock, the liner being deflected laterallythrough aperture 14 into the drain hole. As upper member 34 of the drainhole liner reaches the location of block 43, the member is rotated untilslot 45 reaches the circular position of guide block 43, and thus allowsfurther downward and outward advancement of the drain hole liner. Block43 and recess 45 effectively retain member 34 in the desired relativeposition during further downward advancement, so that member 34 isreceived within aperture 14 in the proper Fig. 7 position. This memberis forced tightly into aperture 14,to make a very tight forced t actingto positively retain the drain hole liner in the position of Figs. 7 and9 relative to the main liner. Tool string 39 is then rotated in acounter clockwise direction to break the threaded connection at 41 andpermit the tool string to be pulled upwardly from the well leaving liner18 in the drain hole.

The next step comprises withdrawing tool string 39 and the whipstockupwardly out of the hole, with the whipstock being suspended from thetool string by virtue of the interengagement of shoulders 29a and 30. Itwill of course be understood that, if desired, tool string 39 asutilized in connection with liner 18 may actually be a portion of thepreviously described drill string 16, in which case shoulder 29a of Fig.6 may be the same shoulder as is shown at 29 in Fig. 3. Followingcomplete withdrawal of the whipstock and tool string from the hole, itis next desirable to shear the uppermost whipstock positioning block 22oil of main liner 11, as by forcing any suitable tool at the lower endof a tool string downwardly against that block. The downward force thusexerted against block 22 shears the preformed shear pins or studs 23,and may permit block 22 to fall to the bottom of the well. Such removalof the uppermost block 22 from liner 1l allows for lowering of thewhipstock into a position of support on the next lower block 22, so that.a second drain hole may be drilled and lined in the above describedmanner. All of the drain holes are successively drilled and lined inthis manner, with the lowermost hole being the last to be formed (seeFig. 9). After this last hole has been formed and lined, the tools areall removed from the well, and the desired multiple drain holearrangement is thus completed.

We claim:

l. Apparatus comprising a main liner to be lowered into the main bore ofa well and having an aperture formed in its side wall, a flexible drainhole liner adapted to be advanced laterally through said aperture andinto a drain hole and having an upper portion for forming a connectionwith said main liner, a whipstock to be lowered into said main liner andhaving a deflecting face adapted to deflect said drain hole linerlaterally through the aperture, means for supporting the whipstoclt inthe main liner at a location to deect said drain 2. Apparatus asdescribed in claim l, in which said l whipstock has a tubular portionthrough which said drain hole liner passes, said guide means comprisinga lug projecting inwardly from said tubular portion and receivable inguiding relation with an axially extending guide recess formed in saidupper portion of the drain hole liner.

3. Apparatus as described in claim 1,- including a lowering stringconnectable to said drain hole liner for lowering it into the well, anda releasable connection between said string and `said upper portion ofthe drain hole liner adapted to be released by movement of the formerfrom the surface of the earth.

4. The method comprising lowering into the main bore of a well, a mainliner having an aperture formed in its side wall prior to lowering,drilling a drain hole extending laterally from said aperture in theliner, and then advancing a flexible drain hole liner through saidaperture and into the drain hole.

5. The method as recited in claim 4, including forming a tightfrictional connection between an upper end of said drain hole liner andsaid first mentioned liner.

6. The method comprising lowering into a well a liner having a preformedaperture in its side wall and having a Whipstock positioning shoulder,lowering a whipstock into said liner to a position of support on saidshoulder, and then drilling a drain hole extending laterally from saidaperture by means of a bit delected through the aperture by saidwhipstock.

7. The method comprising lowering into a well a liner having a preformedaperture in its side wall and having a whipstock positioning lug,lowering a whipstock into said liner to a position of support on saidlug, then drilling a drain hole extending laterally from said apertureby means of a bit deilected through the aperture by said whipstock, andthen shearing said lug off the liner.

8. The method as recited in claim 7, in which said liner has a second ofsaid apertures and a second of said lugs, said method includingsupporting the whipstock on the second of said lugs after shearing ofrrthe irst lug, then drilling a second drain hole at the second aperture,removing the whipstockfrom the well, and shearing off the second lug.

9. Apparatus comprising a main liner to be lowered into the main bore ofa well and having an aperture formed in its wall, a whipstock to belowered into said rnain liner to a location adjacent said aperture andhaving an inclined face for deilecting a member through the aperture andinto a laterally extending drain hole, an interengageable means on saidliner and whipstock acting to support the latter at said location in theformer, said last mentioned means comprising a lug projecting inwardlyfrom said liner, and means forming a positioning recess on saidwhipstoclt for receiving said lug.

l0. Apparatus comprising a main liner to be lowered into the main boreof a well and having an aperture formed in its wall, a whipstock to belowered into said main liner to a location adjacent said aperture andhaving an inclined face for deilecting a member through the aperture andinto a laterally extending drain hole, and interengageable means on saidliner and whipstock acting to support the latter at said location in theformer, said last mentioned means comprising a block carried by andprojecting inwardly from the liner, a shear pin attaching said block tosaid liner, and a recess in said whipstock for receiving said block andhaving an upper wall engageable by the block to support the whipstock inthe liner.

l1. Apparatus comprising a main liner to be lowered into the-main boreof a well and having an aperture f formed in its wall, la whipstock tobe lowered into said mainfliner to a location adjacentsaidapertureandhaving an inclined face -for deecting a member through' the aperture andinto a laterally extending drainY hole, interengageablemeans' on saidliner and whipstock acting to vsupport the latter at said location inthe former, a

flexible rotatable drain hole liner adapted to be deflected whipstockand said drain-hole liner acting to maintainsaid connector portionof-the latter against rotation from a predetermined position relative tothe main liner as thefconnector portion is advanced through saidaperture.

12. Apparatus comprisingV a main'liner to be lowered into the-main bore-of -a Well andhaving an aperture formed in its wall, a whipstock to belowered into said main vliner to a location adjacent said aperture andhaving an inclined face` for deflectinga member through the aperture andinto a laterally extending drain hole, interengageable means on saidliner'and whipstock acting to support the latter'at saidrlocation in theformer, said interengageable means comprising -a block carried by andprojecting inwardly from the' liner, a shear pin attach'- ing said blockto said liner, and a recess in said whipstock for receiving said blockand having an upper wall-engageable by the block to support thewhipstock in the liner,

said apparatus including also a flexible drain hole linerv adapted to bedeflected laterally -by said whipstock face through said aperture andinto a drain hole, said whipstock having a tubular portion through whichsaid drain hole liner passes, ,n and a guide lug projecting inwardlyfrom said tubular portion of the whipstock, said drain hole'v linerhaving an upper portion which is a forced t in said aperture andcontains `a guide recess for movably receiving Asaid lug Ytherebymaintaining said drain hole liner against rotation from a predeterminedposition as the drain hole liner is advanced into ya drain hole.Y

13. Apparatus comprising a mainy liner to be lowered into the main boreof a well and having an aperture preformed in its wall prior tolowering, a whipstock adapted to. be lowered into and relative to saidmain linerv to a predetermined location adjacent said aperture andhaving an inclined face for deilecting a drill bit and drill stringlaterally through the aperture to form a laterally extenddrain hole, andmeans forming interengageable shoulders on said liner and whipstockadapted to engage when the whipstock is moved to said predeterminedlocation adjacent said aperture and acting |to support the whipstockatsaid location, said preformed aperture being of a size to passsaidfbit and string'therethrough without damage to the main linerwhensaid whipstock is said` supported at shoulders.

14. Apparatus as described in claim 13, in which said last mentionedmeans include means carried at the inside of the liner forming one ofsaid shoulders adapted to engage and support the Whipstock in the linerand preformed to be sheared from the liner by downward force.

l5. Apparatus as described in claim 13, including a flexible drain holeliner adapted to be deflected laterally by said whipstock face throughsaid aperture and into a drain hole and having an upper portion whichperipherally engages and is a forced tit within said aperture to form atight frictional connection between said drain hole liner and said mainliner at the aperture.

said predetermined location by References Cited in the tile of thispatent UNITED STATES PATENTS Beck June 5, 1951 UNITED STATES PATENTOFFICE CERTIFICATE OF CORRECTION Patent No., 2,797,893 July 2, 1957 JohnS MoCune et aL It 's hereby certified that error appears .in the printedspecification of the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 6, line l0, for "with an" read Within an",

Signed and sealed this 17th day of September 195'? Attest:

KARL H. AXLINE ROBERT` c. wATsoN ttesting Officer Comnssioner of Patents

